Globe for electric-arc lamps



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L Y Mg B BAILEY.

GLOBE POR BLBGTBIG ARG LAMPS. No. 570,446. Y Patented Novf 3, 18915lUNITED STATES" PATENT OFFICE.

MARCUS B. BAILEY, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-THIRD TO PAULIY. I'IFIERMANS, OF BROOKLYN, NEW YORK.

GLOBE FOR ELECTRIC-ARC LAMPS.

SPECIFICATION forming part of Letters Patent No. 570,446, dated November3, 1896. Application iiled July 1]., 1894. Serial No. 517,207. (Nomodel.)

To all whom it may concern:

Be it known that I, MARCUS B. BAILEY, a citizen of the United States,and a resident of Chicago, in the county of Cook and State of Illinois,have invented certain new and useful Improvements in Globes forElectric-Arc Lamps, of which the following is a specifica* ion. v

The object of my invention is to produce a reflecting-globe that willthrow an even light in a given direction free from shadows and that willmaintain such conditions where the arc varies in its position within theglobe, as in the case of single-feed lamps. To this end I corrugate in apeculiar manner that part of the globe which is to act as a reflectorand of course make it of such material or provide it with such coatingor backing as is desirable Where it is made of glass; and in order toreadily produce the desired corrugations in a suitable and economicalmanner, I prefer to make the globe in sections, that is to say, it maybe divided longitudinallyin two sections, one of which will be of clearglass and the other of which will be a corrugated reflector. I mayfurther divide the corrugated half hori zontally, or the globe may bedivided horizontally in halves and one half corrugated. The parts of theglobe so divided will be held in position by the means of attachment tothe lamp and the wire-netting ordinarily used, or by any suitable means.

In the accompanying drawings, Figure l is a vertical section on the linel l of Fig. 2, and Fig. 2 a horizontal section on the line 2 2 of Fig.l.

A indicates the half of the globe made of clear glass, while B indicatesthe other halfv of the globe, which is opaque and may be of any suitablereflecting material or material provided with a suitablereflecting-surface, though 4I prefer to make this half of glass and giveit a coating such as is applied to the backs of mirrors to give it ahigh reflecting capacity. This reflecting half of the globe may, ifdesired, be formed in two parts, the line ofdivision being a horizontalone. The upper half of the corrugated section is formed with a series ofcorrugations which are divided or separated by vertical or meridianlines b, there being eight such series.

The lines formed .by the apices of the corrugations, the same beingindicated at h', are substantially at about an angle of fortvfivedegrees from the vertical or meridian dividn ing-lines. The corrugationsin one series run in an opposite direction from those in the adjoiningseries, and the lines indicating the apices of the corrugations meet atthe dividing-lines, that is to say, the lines indicating thecorrugations of any two adjoining series are of V shape orinverted-Vshape. The corrugations of the lower section appear asmeridianlines and meet or coincide at the top with the corrugations and meridiandivisionlines of the upper section.

The corrugations of both the upper and lower halves of thereflecting-sections of the globe catch the light and reflect it with adif fused effect, there being no distinct focus behind the carbons, andhence the shadows of the carbons and their carriages or supports are notthrown into or upon the field of light projected by reflection from theglobe. This desirable effect results from the fact that the incidentrays emitted from a center are reflected from the upper section indifferent angular directions, said lines of reflection crossing both asregards the horizontal and vertical fields by reason of the reflectingcorrugations being angularly arranged relativelyT to one another in thedifferent adjacent sections, and that the curvilinear form of the angularly-arranged corrugations causes a general downward deiection of therays, so that the general result is not materially aected bythe graduallowering of the arc due to the burning away of the lower carbon, and thecorrugations in the lower section having primarily a tendencyto throwthe reflected light horizontally.

I prefer to provide the different styles of corrugations in the upperand lowersections in order to insure a uniform reflection of the lightas the arc descends within the globe as the carbons are consumed in thesingle-feed lamp. Where the light is to be reilected downwardly from anelevated lamp, the upper half of the globe will be corrugated, asindicated by the lines h o', and the lower half will be withoutcorrugations. I have found by demonstration that with a reflector ofthis gen- ICO eral character I am enabled to light compar ativelylaigei` areas with a flat uniform appearance of light characterized byan absence of shadows or dark spots.

I prefer to make the globe in sections, as indicated, because of thefacility with which the corrugations may then be formed.

I claim as my inventionl. A globe for an electric-arc lamp having onepart thereof opaque and provided with series of reflecting-corrugationsdivided by meridian lines, the alternate series of corrugations beingangularly arranged in opposite directions between the meridiandividinglines, and having the other part opposite the opaque part ofsuch material and form as to permit the passage of the reiiected light,substantially as set forth.

2. A globe for an electric-arc lamp, having one part thereof opaque andprovided with series of refleeting-corrugations divided by meridianlines, the alternate series of corrugations being arranged at angles ofabout forty-live degrees in opposite directions between the meridiandividing-lines, the ends of the corrugations of the adjacent seriesmeeting together at the meridian lines, and having the other partopposite the opaque part of such material and form as to permit thepassage of the reii ected light, substantially as set forth.

A globe for electric-arc lights, having one side or portion formed ofuncorrugated glass, and the other side or portion opaque and havingreecting-corrugations, the upper half of the latter portion beingprovided With series of corrugations divided by meridian lines fromwhich the corrugations run at an angle of about forty-five degrees, thecorrugations in one series running in the opposite direction fromthosein the adjoining series, and meeting them at the meridian lines, and thelower half of said portion being formed with meridian corrugationscoinciding at the top with the meridian dividing-lines and corrugationsof the upper half.

In testimony whereof I have hereunto subscribed my name.

MARCUS B. BAILEY. lVitnesses:

P. W. HEERMANS, FRANK S. OBER.

